In recent years, due to the spread of devices such as high-accuracy scanners, printers, and computers, there are problems such as counterfeiting and misuse of securities such as bills and checks. Therefore, it is desired that a method and device for accurately recognizing these counterfeits be provided.
Recently, for the case of counterfeits made by means of copying, studies are proceeding with recognizing methods and recognizing devices capable of easily recognizing the authentication of these counterfeits. Further, there have been provided various papermaking machines and printing techniques that are designed for anticounterfeit measures, and bills and the like which are difficult to be counterfeited have been provided.
(Related Art 1)
For example, Patent Literature 1 proposes a recognizing method for recognizing an intaglio printed matter and other printed matters, in which plural light receiving elements, which receive light of the same wavelength, are disposed at different angles with respect to one another, light emitted on bills is received at the plural light receiving elements, and amounts of the received light are compared with one another, whereby the concave and convex sections on the bills are discriminated.
This proposition has a configuration such that point-like light beams are projected sequentially on a surface of the target printed matter along a certain detection line, and it is then determined whether the interrelationship among the amounts of light received at each of the plurality of positions is recognized as an interrelationship when the incident point is even, the plurality of positions being in the vicinity of an angular position, which is symmetric to the incident light, with a virtual normal line at the incident point is the center. Then, if a determination, which is that the interrelationship is not for the case where a result of completion of the detection is even, exceeds a fixed rate determined by the target printed matter, the target printed matter is determined as an intaglio printed matter.
(Related Art 2)
Patent Literature 2 proposes a printed matter reading method and apparatus in which, on a printed matter obtained by using a hue ink in which the hue changes depending on the angle of view, a pair of red and green light beams is projected onto the hue ink section, two light receiving sensors where the acceptance angles are different are used to measure the light beams to discriminate the hue ink on the basis of the difference between the colors and the reflection angle.
This proposition has a configuration such that, when a photo sensor output of the red light, for example, is larger than a photo sensor output of the green light at an observation point A, and when the magnitudes of them are reversed at an observation point B, a printed matter to be determined is determined as a regular printed matter in which specific hue inks, but when reverse of the magnitudes is not observed, the printed matter is determined as a counterfeit.
(Related Art 3)
Patent Literature 3 proposes a counterfeit recognizing device which receives both reflected light and transmitted light from a single light-emitting element and discriminates watermarks of sheets and the like.
This proposition has a configuration such that recognition of the authentication of a bill or the like is performed by reading a watermark pattern of the bill or the like by means of two optical reading means using the transmitted light and the reflected light, and comparing both data items which have been read with each other to check whether they are the same.
(Related Art 4)
Patent Literature 4 proposes a sheet recognition device which has a configuration such that discrimination of the authentication of a sheet is performed by detecting an anticounterfeit stripe provided between both sides of the sheet on the basis of the difference between pattern data, which is obtained by adding the reflection pattern data of the surface of the sheet to the reflection pattern data of the back of the sheet, and the transmission pattern data of the sheet.
Patent Literature 1: Japanese Patent Application Laid-Open No. 6-171071
Patent Literature 2: Japanese Patent Application Laid-Open No. 9-062894
Patent Literature 3: Japanese Patent Application Laid-Open No. 6-203244
Patent Literature 4: Japanese Patent Application Laid-Open No. 6-060242